Officer Jeffrey Sandoz told jurors he initially lied about what happened on Sept. 2, 2005, the day three men drove into a school parking lot with the body of a man who had been shot in the back of their car. Speaking to a grand jury investigating the incident last year, Sandoz said he didn't see anything noteworthy.

But Sandoz, when confronted with evidence that didn't match what he said, later changed the story he told federal investigators. He was granted immunity from prosecution for the lies he previously told FBI agents and grand jurors.

Sandoz was the first of three witnesses called by federal prosecutors this morning, the third day of testimony in the case. Other witnesses included a former photographer with The Times-Picayune and a physician.

Five police officers are on trial for the shooting of 31-year-old Henry Glover and the alleged cover-up that followed. Scheuermann and McRae are charged with beating two men who tried to help Glover, as well as burning his body in a car. Officer David Warren is charged with the shooting. Two other officers -- retired Lt. Robert Italiano and Lt. Travis McCabe -- are charged with writing a false police report about the incident.

The three men who showed up at Paul B. Habans Elementary school were handcuffed and seated on the ground by a car, according to a photograph shown repeatedly by prosecutors.

While they were handcuffed, Scheuermann struck one of the men with the butt of an M-4 rifle, Sandoz testified. McRae later approached one of the men and punched and kicked him, he said.

Sandoz testified that he didn't harm the men. The atmosphere at the time was tense, he said, describing Scheuermann as "agitated."

When questioned by federal prosecutor Jared Fishman, Sandoz admitted he initially lied about all of this, saying he wasn't even sure if Scheuermann or McRae were at the scene.

Sandoz said he lied because he was afraid that if he told the truth, police could have retaliated against him or his family. "I was afraid I would be labeled a rat," he said, adding he was concerned that if he was perceived as cooperating, he later wouldn't receive back-up from fellow officers if he needed it.

Defense attorneys repeatedly pressed Sandoz about his changed story, noting that his immunity agreement shields him from the potential of a multi-year prison sentence if he were convicted of perjury or obstruction of justice.

Jeffery Kearney, who is representing Scheuermann, noted that William Tanner, one of the men who says he was hit by police, originally told a grand jury that he was struck by an officer who had tattoos like the actor Dwayne "The Rock" Johnson.

Sandoz acknowledged that he has large arm tattoos, but said he didn't know about Tanner's allegation. During his trial testimony, Tanner testified that McRae struck him, not the officer with arm tattoos.

A former photographer for The Times-Picayune also witnessed part of the discussions between the three men on the ground and police officers. Alex Brandon, who now works for the Associated Press in Washington, D.C., said he was walking with a federal agent back to the compound when he saw officers talking to men he recalled laying down on the ground.

These men were saying things that were "smart-alecky," Brandon recalled. "I felt like it was a contentious situation."

McRae told Brandon not to take pictures and he obeyed. "It was, for lack of a better term, an order," Brandon said.

However, the agent from the Bureau of Alcohol, Tobacco, Firearms and Explosives, who was with Brandon, did take a picture of the man in the car, Brandon said. When Brandon noted the police said not to photograph the scene, the agent said, "I don't work for them."

Brandon testified he quickly left the scene in search of Capt. Jeff Winn, the SWAT commander, feeling that a "cooler head" was necessary to defuse the situation.

Brandon also testified that he later tried to ask McRae about what happened that day. Sitting at the cafeteria at Habans school, McRae just said, "NAT" and swiped his hand across his neck. In NOPD lingo, NAT means "necessary action taken."

Another witness who testified, Dr. Christobal Mandry, told jurors that he too was likely at the Habans compound that day. Mandry, an emergency room physician, said he witnessed three men handcuffed by a car, although he couldn't be sure it was the same men in this incident.

Mandry said he was never told about a man who had been shot, who was lying in a car not far from the handcuffed men. If he had known, he could have ascertained whether the man was still alive and rendered aid, Mandry said.

Mandry, a reserve officer with the NOPD, was working with the SWAT team during the storm. He is close friends with Winn, he testified.

Brandon also testified that he knew Warren from his time working with him at the Orleans Regional Security Institute. They both worked as instructors to people seeking permits to carry concealed handguns.

About a year after the storm, while at a firing range, Warren told Brandon about shooting a man after Hurricane Katrina.

"I said, 'No, I hadn't heard that before," he said. After Warren told him about the incident, Brandon said he said, "Well, we had a dead guy show up at Habans, maybe that was the same guy."

The story recounted by Warren to Brandon was different than what is generally agreed on by both defense attorneys and prosecutors: that Warren was on the second-floor of an Algiers strip mall containing a substation office of the 4th District. Instead, Brandon thought Warren said the shooting took place while the officer was guarding the 4th District station, which is located near the Mississippi River.

Brandon said Warren told him he shot a man in a car that was approaching. The car wouldn't stop and Brandon had the impression that Warren was in danger of being hit by the car.

"Do you have any doubt in your mind that Warren was certain he hit the man?" Fishman asked.